Shodan is often called "the search engine for hackers," but that's only part of the story. Born out of a seemingly simple experiment, it has evolved into one of the most powerful reconnaissance tools on the internet. Unlike Google or Bing, Shodan doesn't index websites—it indexes devices. And not just computers, but everything from traffic lights and wind turbines to home webcams and smart fridges. If it has an IP address and is exposed to the internet, Shodan probably knows about it.
Created by John Matherly in 2009, Shodan began as a weekend project. He wrote a crawler that scanned the internet and logged what services were running on open ports. Matherly soon realized this “side project” had unearthed a digital goldmine. The early Shodan crawls discovered everything from unprotected power plant control systems to hospital MRI scanners left accessible without passwords. With growing media coverage and cyber-research community attention, Shodan quickly gained notoriety as a tool for identifying ...
Unlike Censys, which is more focused on certificates and structured internet-wide scans, Shodan operates like a rolling surveillance net. Its crawlers scan the internet for specific ports (HTTP, SSH, RDP, FTP, Telnet, etc.) and capture banners—metadata returned by a service when a connection is made. These banners contain rich information: software versions, protocol support, welcome messages, and sometimes even configuration data or credentials exposed by misconfigured devices. Shodan stores all of ...
Over time, Shodan added features that transformed it from a scanner to a platform. It now provides real-time monitoring, API access, bulk export, alerting systems, and integrations with SIEMs and red team toolkits. Governments, corporations, and researchers use Shodan for everything from threat hunting to competitive analysis. During the rise of ransomware in the 2010s, many incidents began with attackers identifying unpatched systems exposed to the internet using tools like Shodan. The 2021 Colonial P...
Shodan is invaluable for open-source intelligence (OSINT). Journalists and investigators use it to identify infrastructure owned or used by organizations and governments. By tying IP ranges to ASN data and device banners, Shodan allows researchers to map networks, correlate usage patterns, and even infer organizational structure. It's been used to expose everything from poorly secured municipal systems to surveillance technologies deployed by authoritarian regimes. Entire research papers have been writ...
Shodan’s user interface is deceptively simple. At first glance, it looks like any other search bar—but type in something like "port:554 has_screenshot:true country:US" and you're stepping into a world of exposed surveillance cams. Search filters include geographic regions, device types, organizations, operating systems, and even SSL certificate parameters. Its power lies in this granular filtering. You can pivot from a single IP to every router of the same make/model on the planet running outdated fir...
The platform operates under the same legal umbrella as Censys: it gathers only data publicly available on the internet. But unlike Censys, which maintains a more academic tone, Shodan embraces its underground appeal. Matherly himself has spoken about the tool’s dual-use nature, and Shodan’s terms of service remind users not to exploit what they find. That said, there's nothing stopping someone from using Shodan data to launch attacks, other than laws—and ethics.
Ethical hackers use Shodan for reconnaissance, especially during penetration testing. It allows them to identify externally facing systems, analyze fingerprinted services, and verify their exposure to the broader web. Red teams can simulate real-world adversaries using the data, often starting their engagement with a few targeted Shodan queries. Meanwhile, blue teams set up Shodan Alerts to monitor their organization's attack surface and detect new exposures or misconfigurations.
On the darker side, black hats exploit Shodan constantly. They automate queries to find vulnerable systems—routers with default creds, databases with no auth, webcams with open ports—and chain them with exploits from Metasploit or private toolkits. Some even sell "Shodan-as-a-service" access in underground forums, providing curated lists of vulnerable devices to less skilled threat actors. The ability to mass-identify targets without scanning yourself lowers the technical bar to entry, and that makes S...
Shodan's database is especially prized for finding IoT devices. Baby monitors, smart thermostats, garage doors, smart TVs—all are indexed. These devices often lack proper security controls, rarely get patched, and tend to expose sensitive data. In one infamous incident, journalists used Shodan to locate unsecured cameras in daycare centers, factories, and even private homes. Some showed families in real time, unknowingly exposed to the internet. While this sparked outrage and policy discussions, it als...
Shodan has also been pivotal during crises. When Russia invaded Ukraine in 2022, cybersecurity researchers used Shodan to monitor changes in digital infrastructure. Similarly, during the COVID-19 pandemic, it was used to track vulnerable health systems and exposed RDP servers as work-from-home exploded. Its role as a passive monitor of internet-connected assets makes it a vital tool for real-time intelligence during dynamic events.
Legally, Shodan sits in the same precarious space as any dual-use tool. It does not break into systems—it merely records what's there. Courts in the U.S. have not clearly ruled on mass scanning, but the prevailing stance is that it’s not illegal *per se* unless paired with intrusion. Still, using Shodan data to gain unauthorized access or even attempting to brute-force passwords is unequivocally illegal under the Computer Fraud and Abuse Act. Many organizations also include usage of tools like Shodan in...
Still, the line between research and intrusion can blur. Gray hats often toe that line, using Shodan to gather intelligence they probably shouldn’t act on—like viewing unsecured traffic cams or dumping banner data of poorly secured appliances. There’s a certain “just looking” culture that persists, arguably made worse by the voyeuristic nature of many Shodan results. Whether this is harmless or deeply unethical depends on who you ask, and how the data is used afterward.
So, what can you do with Shodan?
Fun with Shodan:
— Search for public traffic cameras and view them in real time.
— Find weather stations broadcasting raw telemetry from rural areas.
— Look up industrial control systems (ICS) and see their vendor banners.
— Explore unsecured smart TVs and hotel entertainment systems.
— Identify printers on the internet still using default login credentials.
— Hunt for “honeypot” setups and see how they differ from real services.
— Track global use of outdated services like Telnet or OpenSSH 6.x.
— Generate visual maps of vulnerable services by country or provider.
— Combine filters like “org:Google port:80 html:login” to explore exposed dashboards.
Shodan is a lens into the invisible plumbing of the modern internet. It reveals how unprepared we still are for a world where everything is online, yet few things are secured properly. Whether used for good, evil, or curiosity, Shodan remains one of the most important cybersecurity tools of the past two decades—an equalizer in the asymmetric war of information.